8.4.2 Ex situ Bioremediation
8.4.2.1 Phytoremediation
As the name indicates, with the help of plants, contaminants are kept closer to the
plant body for physical, biological, and microbiological interactions, thereby
decreasing the effect of waste from the water or soil. Important factors to be taken
care of in this system includes—a fibrous root, which may be able to bind to
pollutant based on the depth of the pollutant, the healthy shoot system for translocation from roots to shoot, and further the rate of transpiration depending upon the
xylem flow and xylem sap.
Rhizofiltration/Rhizoremediation is a type of bioremediation in which plants and
associated rhizospheric microbes are used to remove contamination of heavy metals
in soil and water.
8.4.2.2 Land Farming
Depletion of the topmost layer of the soil, like in farming/tilling in order to introduce
aeration, irrigation, and even addition of nutrients like nitrogen, phosphorus, and
potassium. It has been categorized both under in situ (pollutant <1 m below ground
surface) and ex situ (>1.7 m depth).
8.4.2.3 Bioreactor
It utilizes the use of specially designed containers to contain and treat the waste. A
number of bioreactors are available like batch, fed-batch, sequencing batch, continuous, and multistage. The controlled parameters like temperature, pH, aeration rate,
addition of nutrient as per requirement in timely fashion make it more efficient. It has
also been seen that sewage sludge could be effectively utilized via this process and to
improve the bioaugmentation process, even genetically modified organisms could be
used, provided they are not allowed to reach the clean soil or water media, where the
end product is released.
8.4.2.4 Composting
A natural way to dump the waste and wait for it to decompose, by breaking it down,
although the process takes its own due course of time. Two prevalent and widely
used aerobic technologies for composting include:
Biopiles
In case of Biopiles, the emphasis is more on regulation of the different processes
involved like—aeration, irrigation, nutrient and leachation. The only difference
between biopile and composting is addition of organic material to increase the
temperature, thereby making favorable conditions for the growth of microorganisms.
In this process aeration is achieved using plastic pipes, and this process can be done
on large soil areas.
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J. Tomar
8.4.2.1 Phytoremediation
As the name indicates, with the help of plants, contaminants are kept closer to the
plant body for physical, biological, and microbiological interactions, thereby
decreasing the effect of waste from the water or soil. Important factors to be taken
care of in this system includes—a fibrous root, which may be able to bind to
pollutant based on the depth of the pollutant, the healthy shoot system for translocation from roots to shoot, and further the rate of transpiration depending upon the
xylem flow and xylem sap.
Rhizofiltration/Rhizoremediation is a type of bioremediation in which plants and
associated rhizospheric microbes are used to remove contamination of heavy metals
in soil and water.
8.4.2.2 Land Farming
Depletion of the topmost layer of the soil, like in farming/tilling in order to introduce
aeration, irrigation, and even addition of nutrients like nitrogen, phosphorus, and
potassium. It has been categorized both under in situ (pollutant <1 m below ground
surface) and ex situ (>1.7 m depth).
8.4.2.3 Bioreactor
It utilizes the use of specially designed containers to contain and treat the waste. A
number of bioreactors are available like batch, fed-batch, sequencing batch, continuous, and multistage. The controlled parameters like temperature, pH, aeration rate,
addition of nutrient as per requirement in timely fashion make it more efficient. It has
also been seen that sewage sludge could be effectively utilized via this process and to
improve the bioaugmentation process, even genetically modified organisms could be
used, provided they are not allowed to reach the clean soil or water media, where the
end product is released.
8.4.2.4 Composting
A natural way to dump the waste and wait for it to decompose, by breaking it down,
although the process takes its own due course of time. Two prevalent and widely
used aerobic technologies for composting include:
Biopiles
In case of Biopiles, the emphasis is more on regulation of the different processes
involved like—aeration, irrigation, nutrient and leachation. The only difference
between biopile and composting is addition of organic material to increase the
temperature, thereby making favorable conditions for the growth of microorganisms.
In this process aeration is achieved using plastic pipes, and this process can be done
on large soil areas.
160
J. Tomar